Infrared spectroscopy of CO3•−(H2O)1,2 and CO4•−(H2O)1,2

Abstract

Hydrated molecular anions are present in the atmosphere. Revealing the structure of the microsolvation is key to understanding their chemical properties. The infrared spectra of CO3•−(H2O)1,2 and CO4•−(H2O)1,2 were measured via infrared multiple photon dissociation spectroscopy in both warm and cold environments. Redshifted from the free O–H stretch frequency, broad, structured spectra were observed in the O–H stretching region for all cluster ions, which provide information on the interaction of the hydrogen atoms with the central ion. In the C–O stretching region, the spectra exhibit clear maxima, but dissociation of CO3•−(H2O)1,2 was surprisingly inefficient. While CO3•−(H2O)1,2 and CO4•−(H2O) dissociate via loss of water, CO2 loss is the dominant dissociation channel for CO4•−(H2O)2. The experimental spectra are compared to calculated spectra within the harmonic approximation and from analysis of molecular dynamics simulations. The simulations support the hypothesis that many isomers contribute to the observed spectrum at finite temperatures. The highly fluxional nature of the clusters is the main reason for the spectral broadening, while water–water hydrogen bonding seems to play a minor role in the doubly hydrated species.

Carbon Dioxide and Water Activation by Niobium Trioxide Anions in the Gas Phase

“…This effect was shown previously for [CO 3 ] − water clusters employing molecular dynamics simulations, where a comparable water binding motif is present. 62 This leaves two weaker bands for the assignment. First, the small band at 3023 cm −1 .…”

“…The ions were guided with an electrostatic lens system into the cell of a 4.7 T FT-ICR instrument, where they were irradiated using the tunable EKSPLA NT273 (1200−2210 cm −1 ) and EKSPLA NT277 (2250−4000 cm −1 ) laser systems with a maximum pulse energy of 50 and 500 μJ at 1 kHz, respectively. 62 As the laser power for the EKSLPA systems is much lower than that of the free-electron laser, no fragmentation of [NbO 3 ] − and [NbO 2 (OH) 2 ] − was observed. Since IR absorption always competes with emission, the lower energy of the table-top OPO system is likely not sufficient to drive the IRMPD process.…”

Master equation modeling of blackbody infrared radiative dissociation (BIRD) of hydrated peroxycarbonate radical anions

“…•-(H 2 O) 0,1,2 were reported. 32 For the UV-Vis range, cross sections, mostly upper limits, have been measured in several studies for CO 4…”

On the existence of CO32− microsolvated clusters: a theoretical study

“…Importantly, there is no experimental evidence for the existence of [CO 3 ·(H 2 O) n ] 2− microsolvated clusters and only protonated forms [HCO 3 ·(H 2 O) m ] − have been observed. 15–17 Therefore, this raises questions about the stability of [CO 3 ·(H 2 O) n ] 2− clusters toward both autoionization and protonation processes: can they be registered experimentally or not? This question can be addressed by looking at two potential problems: (1) the instability of microsolvated clusters themselves, (2) the peculiar dynamic behaviour of CO 3 2− in a bulk water solvent which serves as a precursor for the synthesis of microsolvated clusters.…”